Vehicles use a variety of heat exchangers, such as an exhaust gas recirculation (EGR) cooler, an exhaust gas cooler, a fuel cooler, an oil cooler or an intercooler. Recently, heat exchangers having a variety of structures are configured inside a waste heat recovery system such that they perform heat exchange using various types of fluid.
In general, it is well known that internal combustion engines used in vehicles, vessels, or the like have a very low heat efficiency. Since only about 30% of fuel supplied to internal combustion engines is used as output energy, improvement in fuel efficiency is needed.
Energy that is not extracted as usable mechanical energy is discharged to the air as waste heat, for example, through the discharge of exhaust gas from an internal combustion engine, charge air cooling, or discharge of engine coolant.
Waste heat recovery systems which promote an improvement in the fuel efficiency by actively recovering such waste heat are currently utilized. Recently, a waste heat recovery system having an organic Rankine cycle is used. Such a waste heat recovery system is configured so as to effectively extract mechanical energy from a turbine by converting working fluid into hot vapor by performing heat exchange with the working fluid and then supplying the hot vapor of the working fluid to the turbine.
Such a waste heat recovery system is provided with an apparatus for generating superheated vapor which converts dry saturated vapor of working fluid into superheated vapor using the high-temperature heat of exhaust gas. It is possible to further increase the efficiency of the turbine by supplying the superheated vapor of the working fluid to the turbine.
Since the apparatus for generating superheated vapor of the waste heat recovery system is configured such that the high-temperature and high-pressure working fluid and the high-temperature exhaust gas exchange heat, it is highly possible that the working fluid may leak and the leaking working fluid may cause severe problems inside a vehicle, which are problematic.